Pre-release process is error prone

[zalberico]

For the behn timer fix we accidentally sent it out on a pre-release moon that was public rather than internal.

This is because we don't have a good doc/process for this to make it easy to do the correct thing.

We also don't have a dedicated moon for internal only releases?

The fix for this:

• We should have very explicitly defined and documented ships for what gets released when.
• The instance names should reflect what they're for. Currently the pre-release instance in glcoud is named after the patp rather than what it's actually for (call it in gcp pre-release moon, public pre-release moon) etc.
• We also need a reference doc for this release process. (canary -> tlon -> tlon and friends -> public)

[zalberico]

This has been started here: https://docs.google.com/document/d/1DMMANXUjT9ClbaKvWYeOtBM5BfPGub_75KvYo1ohn6U/edit

It needs more work to be at the bar to consider this closed.